Workers that can be potentially exposed to electrical arcs and the like need protective clothing and articles made from thermally resistant fabrics. Any increase in the effectiveness of these protective articles, or any increase in the comfort of these articles while maintaining arc protection performance, is welcomed.
A fiber known as polysulfonamide fiber (PSA) is made from a poly (sulfone-amide) polymer and has good thermal resistance due to its aromatic content and also has low modulus, which imparts more flexibility to fabrics made from the fiber; however, the fiber has low tensile break strength. This low tensile strength in fibers has a major impact on the mechanical properties of fabrics made from these fibers, including the ability of the fabrics and garments made with these fabrics to provide adequate arc protection. Therefore what is needed is a way of incorporating PSA into yarns for use in protective apparel that utilizes the benefits of the PSA fiber while compensating for the limitations of the fiber.